Catalytic reforming of non-aromatic hydrocarbons



United States Patent, Q

I e caress. CATALYTIQ REFORMQPJG F NUN-AROMATIC I HYnaocARnoNs JohnArthur Edgar Moy, Peter Thomas White, and Bernard Whiting Burbidg'e, allof Sunbury-on-Thamcs, England, asslgnors to The British PetroleumCompany Llilllted, London, England, a British joint-stock corpo ra H lfoDrawing. Filed Feb. 117, 1958, Ser. No. 715,504 I Claims priority,application Great Britain Feb. 19, 1957 10 Claims. (Cl. 208-=-1 367 Thisinvention relates to the dehydrogenation or dehy drocycllsatlon ofnon-aromatic hydrocarbons andto a catalyst for use in such processes.

According to the present invention, a process for .the

dehydrogenation or dehydrocyclisation of feedstocks consisting of orcontaining non-aromatic hydrocarbons com- P111865 contacting thefeedstock at elevated temperature with a catalyst comprising chromiumoxide on a support, preferably alumina, the catalyst containing also aminor proportion of a spinel. I

The name spinal is given-"to a group of "compounds having a face-centredcubic crystalstructure and having the general formula MM O where M and Mare metal radicals. Thus M may be a monoralent radical and a hexavalentradical (he. M' tlMo or M may be a divalent radical andvMatetravalentradical (i-.e. 2MQ.MO; or M may be a 'tlivalent radical andM a divalent radical ('i'e. M' O M0).

Particularly effective spinels are chromites, for example, cobaltchromite, CoQr O copper chromite,

CuCr- O iron chromite, PEG-3,0 and also titanates, for example,z1nc-titanate;Zn TiO All these spincls' may be prepared artificial-lyandused in that form, but iron chromite also occurs naturally in the orechrome ironstone. This ore may contain .up to 5 0% armors of ironchromite and the use of the ore itself without separation of pure ironchromite. 'is included within the scope of this specification. I Thecatalyst may also contain a minor proportion of other promoting elementsfor example an alkalimetal; particularly potassium. V

The process is preferably carried out at a pressure of not more thanp.s.i.g. and without recycle, of the hydiogen-containing gas produced inthey process or addition ofeirtraneous hydrogen. An appreciable quantityof such gas is produced, which is available. as a valuable byproduct,.The term not more than 50 'p.s.i.g. in chides atmospheric pressure orbelow, atmospheric pressure being, in fact, preferred. The preferredtemperaone range 450 to 580 C. and the space velocity may 0.1 to 1.0v./v./hr. When used within the process conditions set out in thisparagra h it has been found that the spinel promoted' chroma/aluminacatalysts aremost elfe'ctive under severe processing conditions. givingprodnets. with research octane numbers (clear) of 100' or more. At thishigh octane number levels the decrease in yield with increase in octanenumber is less rapid with spinel-promoted chromia/alumina catalyststhan. with,

for example, a known catalyst of chromia/alummaprcniot'cd witlrceriumand potassium. Hence the yield for a git/en octane number is greater.

The catalyst maybe used in the form of a fixed bed, a bed or a fluidisedbed; Since the catalyst is readily regenerated by burning 'oficarbonaceous deposits in a stream of oxygen-containing gas, it is,articularly suitable for fluidised or moving bed processes.

The feedstocks used may be pure hydrocarbons, for example straight-chainpar amns or eycle araflins, or tures of hydrocarbons boiling thegasoline or "ice Patented Sept. 26, 1961 2 naphtha range. A particularlypreferred feedstock is a C to C11 non-aromatic hydrocarbon or a mixturecon:- sisting predominantly'of C toC- non-aromatic hydrocarbons. v d

Thus according to one embodiment of the Invention the feedstock may be astraight-run feedstock, partic ularly a lower-boilin straight-runfraction commonly known as light gasoline. By treatment according to.the present invention gasoline blending components of octane number andhigh volatility may be prepared from such feedstocks, in particulargasoline blending com onents having a research octane number (clear) ofat least and avolatility of at least 70% evaporatedat C. 1 V 1Acc'orZ-l-ing to a further embodiment the feedstock may be the productofaprevious catalytic reforming process so that the present inventionincludes a two-stage reforming process designed to produce aromatics andhigh octane gasoline fractions with preferably a research octane nurnber (clear) of the order of 100. Any convenient'reform ing process maybe used, as the first stage, but those employing a catalyst of platinumon a support contalnmg aluminum oxide with or without halogen'arepreferred, such processes being hereinafter referred to as platinumreforming processes and the products as platinum reformates.

With a two-stage process, the whole of the reform-ate. from the firststage may be reformed in the second stage,

"but since 'the' higher boilingend is rich in aromatics which are notsusceptible to further upgrading, the r e-formats prefer-ablyfractionated to give a lower-boiling relatively aromatic-free fractionwhich is subjected to the further treatment. Alternatively the reformatemay be. solvent extracted and the r'aflinatel or a fraction thereofsubjected to the further treatment. If desired, the product may berecombined with the higher boiling fraction or the solvent extract asthe case, maybe, butit may also becombined with other high octanecomponents for example heavy cat. cracked gasoline or alkylate. Thepresent invention includes a dehydrogenation or dehydrocyclisaticncatalyst comprising chromium, oxide on a support, preferably alumina,and aminor proper. tion of aspinel. Particularly effective. spinels arecobalt; copper and iron ch-rornites, and zinc titanate. The preferredproportions, byweight of the material stable at 1020 F.,. are within thelimits: Chromium oxide 5% to 25%. I Spinel s 0.1% to 10%, particularly"2% to 5% (butl'essthan the chromium oxide). Other promoting elements V(expressed as oxide), 0.1% to 5%.. Alumina Balance.

The catalyst maybe prepared by any convenient tech: nique such asco-preci itation or impregnation."

The invention is illustrated by the following examples.

EXAMPLE 1 A copper chromite/chormia/alumina catalyst was prepared asfollows: Copper chromite was prepared by roasting an intimate mixture ofcopper nitrate. and chromic oxide for two hours at 700 C. (1292 -F.).The product was extracted with hot dilute nitric acid, washed and dried.t g. copper chromite were suspended in a solution of 13 26 g. aluminiumnitrate in 1 /2 1. distilled water. 650 Anala-rammonia solution (-sp.gr. 0.88) were added with vigorous stirring. The slurry was filtered,washed 6 1. Warm distilled water and linally with '1 litre 4% vol.acetic acid solution. The filter cake was dried overnight at 50 C., for3 hours at 120 C. and calcined at 550 C. for 2 hours. The calcinedmaterial was pelleted to in. and impregnated with 28 g. Analar chromiumtrioxide dissolved in 80 ml. distilled water. The

catalyst was dried at 120 C. and calcined at 550 C. 5

for 2 hours.

EXAMPLE 2 A reformate obtained by reforming a straight-run naphthafraction over a catalyst of platinum, alumina and combined halogen wassplit into light and heavy fractions, the light fraction having an endboiling point of 108 C. and a research octane number (clear) of 76.1.This light platinum reformate was further reformed under the followingconditions:

Pressure Atmospheric. Space velocity 0.2 v./v./hr. Recycle gas None.Processing period 5 hours. The results are shown in Table 1 below.

Table 1 Dehutanized ll uid Exit gas product q ReactionCatalysteompositemperation ture, Yield, Octane Flow H, eon- 0. percentnumber, rates tent, perwt. research, s.c.i./b. cent vol.

clear (1) 10% CHOI/ 41s 75 94.2 ass so m ar s30 61 100.1' 1,865 17 41s79' 94.7 "1,140. 7s 81K? s30 59 102.6 2,200 or a) 10% 475 11 9s a 1 170as gggggj s30 52 104.4 212.40v ea (4) abort-1% 41s 91 14.4 60 30 (a)time a a 0001,01? sea 42 are 2,620 as From the table it will be seenthat runs 2 and 3 using catalysts containing both chromium oxide andcobalt chromite supported on alumina gave products with appreciablyhigher octane numbers than runs 1, 4 and 5 in which the catalystsconsisted of an alumina base sup- 45 porting only one of the chromiumcompounds, i.e., either chromium oxide or cobalt chromite but not both.

EXAMPLE 3 A light, staight-run gasoline fraction having an end boilingpoint of 112 C. and a research octane number (clear) of 61.2 wasprocessed under the following conditions over a catalyst consisting of10% chromia on alumina promoted with 2% cobalt chromite.

Pressure Atmospheric. Space velocity 0.2 v./v./hr.

Recycle gas None.

Processing period 5 hours.

Catalyst Chromium oxide and cobalt chromite supported on alumina. Theresults are set out in Table 2.

4 EXAMPLE 4 Pressure n. Atmospheric.

Space velocity 0.2 v./v./hr.

Recycle gas None.

Processing period 5 hours.

Catalyst Chromium oxide and copper chromite supported on alumina. Theresults are set out in Table 3.

Table 3 Debutantred liquid Exit gas product Reaction temperature, 0.

Yield, Octane Flow H1 conpercent number, rate, tent,perwt. research,s.c.t./b. cent vol.

clear EXAMPLE 5 Example 4 was repeated using the same feedstock andprocess conditions but with a catalyst consisting of 10% chromia onalumina promoted with 2% zinc titanate.

The results are set out in Table 4.

Table 4 Debntanized liquid Exit gas product Reaction temperature, 0.

Yield, Octane Flow H, eonpercent number, rate tent,perwt. research,s.c.i./h. cent vol.

clear EXAMPLE 6 Naturally-occurring chrome ironstone ore contain ingabout 50% of iron chromite spinel was ground to a particle size of lessthan 40 microns. 10 g. of this ground chrome ironstone were suspended ina solution of 1326 g. aluminium nitrate in 1% litresdistilled water. 650ml. Analar ammonia solution (sp. gr. 0.88) were added with vigorousstirring. The slurry was filtered and washed with 6 litres warmdistilled water. The filter cake was dried overnight at 50 C., for 3hours at C. and calcined at 550 C. for 2 hours; The calcined materialwas impregnated with 28 g. Analar chromium trioxide dissolved in 80 ml.distilled water. The catalyst was dried at 120 C. and calcinced at 550C. for 2 hours.

' EXAMPLE 7 I A light platinum reformate having the same boiling rangeand research octane number (clear) as that used in Example 4 wasprocessed under the following conditions Reaction temperature 530 C.Pressure Atmospheric. Space velocity 0.2 v./v./hr. Recycle gas None.Processing period 5 hours.

Comparative runs were carried out using different catalysts. Thecatalysts used and the results obtained are set out in'Table 5 below.

Table 5 Debra tanised liquid Exit gas product Catalyst Yield, On Flow HIeonpercent (Res.) rate tent, perwt. clear sci/i). cent vol.

10% chromla on alumina, promoted with 1% cerium and 1% potassium 67.100. 6 l, 846 83. 2 10% chromia on alumina promoted with 5% chromeironstone" (as prepared in Example 6)..-. 50. 4 103. 9 2, 138 74. 8

EXAMPLE 8 Further runs were carried out using the light platinumreformate of Example 7, under the same conditions of pressure, spacevelocity and processing period and the same absence of recycle gas as inExample 7. A wider range of temperatures was, however, used. Twocatalysts were tested-a chromia/ alumina catalyst promoted withsynthetic iron chromite, prepared in a manner similar to that describedin Example 1, and a chromia/alumina catalyst promoted with 5% chromeironstone and also 1% of potassium oxide.

The temperatures used and the set out in Table 6 below.

results obtained are 1. A process for the treatment ofa hydrocarbonfeedstock containing at least a major proportion of non-aromatichydrocarbons to produce a product having an increased aromatic contentcomprising contacting the hydrocarbon feedstock in a reaction zone witha catalyst consisting essentially of, by weight of the total catalyststable at 1020 F., 5 to 25% chromium oxide, 0.1 to 10% of a spinelhaving a face-centered cubic crystal structure and having the generalformula MM' O wherein M and M are difierent metal radicals, and balancealumina, the amount of said spinel being less than that of the chromiumoxide, at a temperature of from about 450 to 580 C., at a pressure notin excess of about 50 p.s.i. ga., and in the absence of added hydrogento the reaction zone, and recovering a product having an increasedaromatic content.

2. A process for the treatment of a hydrocarbon feedstock containing atleast a major proportion of non-aromatic hydrocarbons to produce aproduct having an increased aromatic content comprising contacting thehydrocarbon feedstock in a reaction zone with a catalyst consistingessentially of, by weight of the total catalyst stable at 1020 F., 5 to25% chromium oxide, 0.1 to 10% of a spinel having a face-centered cubiccrystal structure, said spinel being selected from the group consistingof metal chromites and metal titanates, and balance alumina, the amountof said spinel being less than that of the chromium oxide, at atemperature of from about 450 to 580 C., at a pressure not in excess ofabout 50 p.s.i. ga., and in the absence of added hydrogen to thereaction zone, and recovering a product having an increased aromaticcontent.

3. A process as claimed in claim 1, wherein the catalyst contains 2% to5% of spinel.

4. A process as claimed in claim 1, wherein the catalyst contains also0.1% to 5% of an alkali metal, expressed as oxide.

5. A process as claimed in claim 1, which is carried out at a spacevelocity of 0.1 to l v./v./hr.

6. A process as claimed in claim 1, wherein the prodnot has a researchoctane number, clear of at least 100.

7. A process as claimed in claim 1, wherein the feedstock is selectedfrom the group consisting of C to C non-aromatic hydrocarbons andmixtures consisting predominantly of C to C7 non-aromatic hydrocarbons.

8. A process as claimed in claim 1, wherein the feedstock is astraight-run distillate.

9. A process as claimed in claim 1, wherein the feedstock is selectedfrom the group consisting of catalytic reformates and portions thereof.

10. A process as claimed in claim 9, wherein the catalytic reformate isa platinum reformate.

References Cited in the file of this patent UNITED STATES PATENTS2,278,223 Sturgeon Mar. 31, 1942 2,584,531 Arnold et al. Feb. 5, 19522,658,858 Lang et a1 Nov. 10, 1953 2,822,336 Polack Feb. 4, 19582,846,365 Gladrow Aug. 5, 1958 UNITED :STATES PATENT. OFFICE CERTIFICATEOF CORRECTION Patent. N06 give-(2)1329 p er 12m 1961 John Arthur.Ejjigar Moy et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below Colunm 4 ,l-ine 3 for "a straight run; naphtha read m astrmght-run naphtha column 6', line 32 for Inumber clear of at least",read number cl'ear o'f at east l I I Signed and Sealed this 3rd day ofApril 1962 S EA L) Attest:

ERNEST'W. SWIDER DAVID L. LADD Attesting Officer Q Commissioner ofPatents

1. A PROCESS FOR THE TREATMENT OF A HYDROCARBON FEEDSTOCK CONTAINING ATLEAST A MAJOR PROPORTION OF NON-AROMATIC HYDROCARBONS TO PRODUCE APRODUCT HAVING AN INCREASED AROMATIC CONTENT COMPRISING CONTACTING THEHYDROCARBON FEEDSTOCK IN A REACTION ZONE WITH A CATALYST CONSISTINGESSENTIALLY OF, BY WEIGHT OF THE TOTAL CATALYST STABLE AT 1020*F., 5 TO25% CHROMIUM OXIDE, 0.1 TO 10% OF A SPINEL HAVING A FACE-CENTERED CUBICCRYSTAL STRUCTURE AND HAVING THE GENERAL FORMULA MM''2O4, WHEREIN M ANDM'' ARE DIFFERENT METAL RADICALS, AND BALANCE ALUMINA, THE AMOUNT OFSAID SPINEL BEING LESS THAN THAT OF THE CHROMIUM OXIDE, AT A TEMPERATUREOF FROM ABOUT 450 TO 580* C., AT A PRESSURE NOT IN EXCESS OF ABOUT 50P.S.I. GA., AND IN THE ABSENCE OF ADDED HYDROGEN TO THE REACTION ZONE,AND RECOVERING A PRODUCT HAVING AN INCREASED AROMATIC CONTENT.